Bridgeton Formation — Summary. 23 



The great river which flowed from the northeast to Trenton 

 or Bordentown probably held this course long after the deposition 

 of the Bridgeton gravels — long enough, indeed, to remove that 

 formation from a belt 5 to 10 miles wide. Knapp thinks there 

 is some evidence that before the deposition of the Pensauken 

 formation, small streams comparable to the upper Millstone 

 River, Manalapan Creek, and Assanpink Creek, heading in the 

 Clarksburg region, flowed northwest across the lowland, some 

 of them turning finally to the northeast, and some to the south- 

 west. Before the Hudson was diverted, it had developed a low- 

 land 30 to 50 feet below the prevailing pre-Bridgeton level. 



If the above conclusions are correct, the Hudson was diverted 

 before the deposition of the Pensauken gravels. The method 

 of diversion is not known. If it was not by piracy, it may have 

 been by wave cutting, which conceivably opened up connection 

 between the sea and that part of the stream above Staten Island. 

 Knapp thinks that the first diversion of the Hudson from its old 

 valley was not to its present course, but that it was either east- 

 ward, north of Long Island, or, following the suggestion of 

 Veatch, across the western end of Long Island in the vicinity of 

 Jamaica. 



Whatever the time of the diversion of the Hudson, and what- 

 ever its course in pre-Pensauken time, it seems to have reestab- 

 lished its course to the southwest during the Pensauken epoch. 

 This might have been the result of the blocking of the eastern 

 outlet by glacial drift, or by outwash from the ice in the glacial 

 epoch contemporaneous with the deposition of the Pensauken 

 formation. 



The above hypothesis as to the former course of the Hudson is 

 not without difficulties. Thus the surface of aggradation should 

 have been at least 50 feet higher, say at Freehold, than at Berlin, 

 to make transportation to the south westward possible. If it had 

 been built up 50 feet higher at Freehold than at Berlin, the 

 gravel would have been carried over the divide to the southeast, 

 unless the divide was then higher (which is not improbable) 

 than now ; but gravel of this sort is not found southeast of the 

 divide. Again if the Freehold divide was then high enough to 



